Add ability to provision Test Kitchen instances that are reachable
over SSH. For this, specify the name of a running instance using -K
(or --kitchen).

IMPROVEMENTS:

Use run list from JSON file if it contains the run_list attribute.
Recipes passed on the command line will still override this list, andrecipes/default.rb is still the default. (Thanks to @arosenhagen who
requested this feature.)

Strip all non-cookbook files after resolving dependencies. This
ensures that only essential cookbook files are copied to target
machines, further saving time.

Report overall duration when chef-runner is done.

Extend script/build to auto-generate chef-runner’s Homebrew
formula when building a new release with --release.